Pressure responsive switch

ABSTRACT

This invention relates to a normally open pressure responsive electrical switch. Such a switch can be used in an automobile transmission as part of the transmission control spark advance systems presently found on automobiles.

[ Feb. 27, 1973 3,553,402 1/1971 Hire ........200/83 P 2,864,918 12/1958 .200/67 DA X [54] PRESSURE RESPONSIVE SWITCH Epstein [75] Inventor: Donald J. Zelenka, Flushing, Mich.

General Motors Corporation, FOREIGN PATENTS OR APPLICATIONS [73] Assignee:

1,008,097 5/1952 France..............................,.200/83 R Detroit, Mich.

Oct. 4, 1971 [22] Filed:

Primary ExaminerRobert K. Schaefer Appl' l86024 Assistant Examiner--Robert A. Vanderhye Attorney-Sidney Carter et al.

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References Cited in an automobile transmission as part of the transmission control spark advance systems presently found on UNITED STATES PATENTS automobiles- 3 Claims, 3 Drawing Figures 3,090,848 Scholz V PATENTED -3',718.790

I N VEN TOR.

A T TORNE Y PRESSURE RESPONSIVE SWITCH The prior art switches such as that shown in the US. Pat. to Clason No. 2,816,189, assigned to the same assignee, are of the normally closed type switches which cannot be used in the transmission control spark system application without an additional relay.

By use of my invention I provide a simple-to-manufacture switch that is normally open and which has a minimum number of parts.

i It is an object of my invention to provide a simple, normally open pressure responsive switch. Other objects and advantages of the present invention will be apparent from the drawings in which:

FIG. 1 shows a cut-away view of one embodiment of my invention;

FIG. 2 shows a similar view of a second embodiment; and

FIG. 3 shows the contact assembly as used in the FIG. 2 embodiment.

Referring to FIG. 1, body member is formed as two members or in two parts or sections. The first section is a cup-shaped member 12 made of a conductive material and having an integral tubular boss or neck portion 14 formed thereon with the neck portion 14 having a fluid passage 16 therein. Neck 14 has threads 18 thereon for easy attachment. Cup-shaped member 12 has an external hexagonal shape so that it may be readily engaged by a spanner wrench or similar tool. However, it is understood that the shape is immaterial and therefore the body may be made in any convenient shape or form.

The second section of body member 10 is similarly formed as a cup-shaped member 20 as is the first section 12 of body member 10 and likewise has a tubular boss or neck member 22 integrally formed thereon and having a bore 24 therethrough. Second section 20 of body member 10 is made of an insulator material, such as rubber, plastic or the like. Cup member 20 fits into cup member 12 with the two members 12 and 20 held in an assembled position by a crimped or rolled-over edge 28 formed on member 12. It is understood that any convenient means, such as bolts, screws, epoxy or the like, may be used to hold the two members together.

A flexible diaphragm 30 made of any. known diaphragm material is held between the two cupshaped members 12 and 20 by conductive discs 32, 34 respectively, as well as the force of the crimp acting to hold the two members together. The first disc 38 has holes therethrough to allow fluid to move through the disc and impinge on the diaphragm to aid the diaphragm in its movement. As is readily apparent, conductive disc 32 is the stationary contact.

Centrally located within a cut-out or stepped-out portion 40 in the conductive cup member 12 is a movable contact 42. Contact 42 is inserted through disc 32 and the diaphragm 30 where it is held in this position by a peened or rolled-over edge 44 on the contact body 46. An insulator member 48 is located between contact body 46 and the conductive disc or stationary contact 32 and is held in position on diaphragm 30 by means of protrusions 50. Below diaphragm 30 and between disc 32 is a sealing gasket 31 that acts as a seal between members 12 and 20. The peened-over edge 44 on contact body 46 in addition to holding the contact 42 in place also holds a third conductive disc 52 in a fluid tight manner beneath diaphragm 30. Disc 52 reinforces diaphragm 30 and acts or serves as a seat for the conductive spring 54 and also makes up part of the electrical path through the switch. Spring 54 is attached to a fourth conductive disc or plate 56 that is in turn attached to a terminal 58 through a body 60. Body 60 has rolled-over or peened edges 62 to hold the fourth conductive disc to the terminal 58.

A modification of the pressure responsive switch is shown in FIG. 2. The switch is constructed in the same manner and operates in the same way as the switch shown in FIG. 1. The difference, however, is in .the movable contact member or contact plate 64. Contact member 64 is positioned in a cut-out or stripped-out portion in a conductive member 65 and is held inthat position by a first conductive disc 66, which we will also call the stationary contact, diaphragm 68, insulator 70, 71, the force of the crimp holding the two body sections 65, 67 together, as well as the force of the spring 69 acting against the diaphragm and the first conductive disc 66. Contact member 64 is insulated from the conductive disc 66 by insulator member 70. Diaphragm 68 is reinforced by means of the clips 72 and is held in position by spring 69 and conductive member 66. Clips 72 also act as a seat or means of holding spring 69 in place. Disc 66, clips 72, spring 69 and a terminal member (not shown) serve as the electrical path from contact 64 to ground.

As shown in FIG. 3, contact plate 64 is made in a generally circular shape having a cut-out finger 76. Plate 64 is made of a conductive material preferably of spring steel and is bowed at the mid-point 78 toward the edges. As readily seen in FIG. 3, in a relaxed state, with no pressure on the outside of the contact plate, the finger 76 generally protrudes or projects out of the plane of the contact plate. Insulator is assembled to the contact. In the assembled position and when pressure is applied through the assembly of the parts of the diaphragm 68, conductive disc 66, etc., contact plate 64 is bent or assumes a flat configuration as shown in FIG. 2, causing finger 76 to also move into a flat or planar position or configuration.

In use, the boss or neck 14 having threads 18 thereon is screwed into an opening generally in communication with a source of fluid under pressure in this case, in the transmission and the terminal 58 is connected to the battery. This will provide a signal to the distributor to advance or retard the spark. In the operation of the switch shown in FIG. 1, when fluid pressure on the diaphragm 30 entering through passage 16 exceeds the pressure applied by spring 56, the diaphragm moves towards terminal 58 thereby moving contact 42 in engagement with the conductive disc 32 to provide the signal required.

In the operator of the second embodiment switch shown in FIG. 2, as fluid pressure on the conductive disc 66 and diaphragm 68 exceeds spring pressure, they move toward the spring and away from the fluid passage 73. This action takes pressure off of the outside edges of contact plate 64 causing or allowing the plate to relax as shown in FIG. 3, whereby the finger 76 moves upwardly to the dotted line position 75 shown in FIG. 2, to make contact with conductive disc 66 to close the circuit and provide the signal desired. As is readily apparent, conductive disc 66 is a second contact.

l have provided a simple normally open pressure responsive switch that has a minimum number of parts that can be readily and easily assembled.

While my invention has been described in terms of certain specific embodiments thereof, it should be appreciated that other forms might be adapted by one skilled in the art; and, therefore, the scope of my invention is not to be considered limited by the specific embodiments disclosed.

I claim:

1. A pressure responsive electrical switch that makes electrical contact in response to a change of fluid pressure comprising a conductive body member, an insulator body member integrally attached to said conductive body member, a diaphragm secured between said conductive body member and said insulator body member by a first and second conductive disc, said first and second conductive discs being the stationary contact, a movable contact, said movable contact being inserted through said stationary contact and said diaphragm with said movable contact secured in a fluid tight relationship to said diaphragm by means of a third conductive disc on the side of said diaphragm opposite said stationary contact and being located in said insulator body member, insulator means between said movable contact and said stationary contact, a fourth conductive disc opposite said third conductive disc in said insulator body member having a terminal thereon, a spring between said third and fourth conductive discs that provides an electrical path from said movable contact to said terminal, said conductive body member having a fluid passage therein whereby fluid forced into the passage will act on said diaphragm to move said diaphragm and therefore said movable contact into engagement with said stationary contact whereby the switch electrically goes from a normally open to a normally closed position, said conductive body member having means of securing said pressure responsive switch to a fluid source.

2. A pressure responsive electrical switch that makes electrical contact in response to a change of fluid pres sure comprising a conductive body member, an insulator body member integrally attached to said conductive body member, a diaphragm secured between said conductive body member and said insulator body member, a first conductive disc secured to said diaphragm and also secured between said conductive body member and said insulator body member, a contact member secured on a ledge and in contacting relationship with said conductive body member and being insulated from said first conductive disc by an insulator means, said conductive disc, spring insulator means, the conductive body and insulator body members providing a means of pressure on the edges of said contact member to change the shape of said contact from an initial generally curved position to a generally planar position, a second conductive disc on the opposite side of said diaphragm from said first conductive disc having a terminal thereon, a spring between said first and second discs that provides an electrical path between said conductive discs to said terminal, said conductive body member having means of securing said pressure responsive switch to a fluid source, a fluid passage in said conductive body member whereby fluid into the passage having enough pressure to overcome the spring pressure will impinge on said diaphragm to move said diaphragm against said spring thereby removing pressure from the edges of said contact member whereby said contact member returns to its initially curved position to make contact with said conductive disc to close the circuit and provide the desired signal.

3. In a switch as set forth in claim 2 wherein the contact has a struck-out center finger portion that moves in relationship to fluid pressure on said diaphragm whereby upon pressure that exceeds spring pressure being applied to said diaphragm said pressure on the outside edges of said contact relaxes whereupon said center finger portion moves out of the plane of said contact to engage said conductive disc. 

1. A pressure responsive electrical switch that makes electrical contact in response to a change of fluid pressure comprising a conductive body member, an insulator body member integrally attached to said conductive body member, a diaphragm secured between said conductive body member and said insulator body member by a first and second conductive disc, said first and second conductive discs being the stationary contact, a movable contact, said movable contact being inserted through said stationary contact and said diaphragm with said movable contact secured in a fluid tight relationship to said diaphragm by means of a third conductive disc on the side of said diaphragm opposite said stationary contact and being located in said insulator body member, insulator means between said movable contact and said stationary contact, a fourth conductive disc opposite said third conductive disc in said insulator body member having a terminal thereon, a spring between said third and fourth conductive discs that provides an electrical path from said movable contact to said terminal, said conductive body member having a fluid passage therein whereby fluid forced into the passage will act on said diaphragm to move said diaphragm and therefore said movable contact into engagement with said stationary contact whereby the switch electrically goes from a normally open to a normally closed position, said conductive body member having means of securing said pressure responsive switch to a fluid source.
 2. A pressure responsive electrical switch that makes electrical contact in response to a change of fluid pressure comprising a conductive body member, an insulator body member integrally attached to said conductive body member, a diaphragm secured between said conductive body member and said insulator body member, a first conductive disc secured to said diaphragm and also secured between said conductive body member and said insulator body member, a contact member secured on a ledge and in contacting relationship with said conductive body member and being insulated from said first conductive disc by an insulator means, said conductive disc, spring insulator means, the conductive body and insulator body members providing a means of pressure on the edges of said contact member to change the shape of said contact from an initial generally curved position to a generally planar position, a second conductive disc on the opposite side of said diaphragm from said first conductive disc having a terminal thereon, a spring between said first and second discs that provides an electrical path between said conductive discs to said terminal, said conductive body member having means of securing said pressure responsive switch to a fluid source, a fluid passage in said conductive body member whereby fluid into the passage having enough pressure to overcome the spring pressure will impinge on said diaphragm to move said diaphragm against said spring thereby removing pressure from the edges of said contact member whereby said contact member returns to its initially curved position to make contact with said conductive disc to close the circuit and provide the desired signal.
 3. In a switch as set forth in claim 2 wherein the contact has a struck-out center finger portion that moves in relationship to fluid pressure on said diaphragm whereby upon pressure that exceeds spring pressure being applied to said diaphragm said pressure on the outside edges of said contact relaxes whereupon said center finger portion moves out of the plane of said contact to engage said conductive disc. 